Microfluidics is directed toward methods and apparatus for handling very small, for example, nanoliter to attoliter, volumes of fluids. Microfluidic devices typically contain chambers, channels and/or other components having sizes on the micrometer scale. Microfluidic systems have diverse and widespread potential applications. For example, technologies which include microfluidic components include inkjet printers, blood-cell-separation equipment, and equipment which performs biochemical detection, biochemical assays, biodefense assays, biohazard assays, chemotaxis assays, cell culture, chemical synthesis, combinatorial chemistry, crystallization, drug screening, electrochromatography, genetic analysis, laser ablation, mechanical micromilling, medical diagnostics, microdiagnostics, polymerase chain reaction (per), solvation assays and surface micromachining.